Tachistoscope



Jan. 30, 1962 K F. KURZ 3,018686 TAGHISTOSCOPE Filed Jan. 10, 1951 6Sheets-Sheet 1 IN V EN TOR.

KARL KURZ BY BUCKHORN, CHEA 77-MM r BLOAE A T7'ORA/EYS Jan. so, 1962 K.F. KURZ 3 TACHISTOSCOPE Filed Jan. 10, 1961 6 Sheets-Sheet 2 IN VEN TOR.

KARL KURZ K. F. KURZ TACHISTOSCOPE Jan. 30, 1962 6 Sheets-Sheet 3INVENTOR.

KARL KURZ BUCKHOQN,CHEAWAM" BLORE F'iled Jan. 10, l961 K. F. KURZTACHISTOSCOPE Jan. 30, 1962 6 Sheets-Sheet 5 Filed Jan. l0 1961INVENTOR.

KARL KURZ Jan. 30, 1962 K. F. KURZ 3,018686 TACHISTOSCOPE Filed Jan. 10,1961 6 Sheets-Sheet 6 IN V EN TOR;

United States Patent Ofiice 3,61%,36 Paxter1xibed Jan. 30, 1962 3018,686TACHISTOSCOPE Karl F. Kurz, Portland, Oreg. assignor to Sawyers inc.Progress, Oreg., a corporation cf Oregon Filed Jan. 10, 1961, Sex. N0.81,756 7 Claims. (C11. 38-27) The prcsent invention comprises animprovement in tachistoscopes. The particular frrn of tachistoscope isone which is adapted to receive and rotatabl3 guide a disc holding aconcentric row of transparencies, disc feeding means rnovable from arest osition to an advanced position for rotating said disc one stepduring each such movernent thereof whereby successively to plane saidtransparencies at a projecting aperture, and means to return saidfeeding means to its rest position. Such a projector is disclosed andc1aimed in the patent to Smith N0. 262507 8, issned January .13, 1953,and the patent 10 Paulsohn N0. 2,916964, issued December 15, 1959, towhieh reference may be made for details which rnay n0t becompletelyapparent from the instant disclosure.

An Object of the present invention is to provide means in a projector ofthe type described whreby the duration 0f projection o-f an image may beaccurzitely and variabiy controlled, such rneans comprising a pair ofshutters, shutter latching mechanisrn, and timing mechanism, such asdisclosed and claimed in the patents 10 Smith N0. 2,671390, issued March9, 1954, and N0. 2680400 issued Inne 8, 1954, to which reference may bemade f0r details which may not be compietely disclosed in the instantapplication. By means of the improved apparatus herein disclosed, thetime of exposi1re of an image may be set a1; any desired fretional partof a sec-ond, er may be manuaily controlled for langer exposures, suchas two seconds er longer.

A further object of the present invention is to pr0vic'xe means in adevice of the character described whereby a preselected portion of atransparency may be projected, or the entire transparency may beprojected.

A further object of the present invention is to provide means in adevice of the character described ab ove Whereby each transparency of apiurality f transparencies positioncd in a concentric row upon a discholder may be successively positioned in projecting position oppesite aprojecting aperture in the projector, such positioning beingaccomplishedat each movernent o-f a feeding mechanism fro-m a restposition to an advanced position, in which the feeding meehanism rnay berendered imperative to advance the disc while actuating the shuttcrmechanism, so that a selected image may be repeatedly projeeted asdesired.

The foregoing and other 0 bjects and advantages 0r the present inventionWill be readily apparent frorn inspection of the following specificationtaken in conneetion with the accompanying drawings wherein like numeralsrefer 10 like parts throughout, and in which a prcferred forrn cf theinvention is illustrated and described.

In the drawings,

FIG. 1 is a view, in perspective, of the tachistoscope of the presentinvention mounted upon the base cf a carrying case;

FIG. 2 is a view, inelevation, frorn the right side of FIG. 1, withparts broken away;

FIG. 3 is a partia1 p1an view cf FIG. 1 With parts broken away;

FIG. 4 is a partial vertical section taken substantially a1ong line 4401 FIG. 3, with portions of the mechanism removed for clarity; 1

FIG. 5 is a view similar to FIG. 4, showing the disc feeding meansmounted thereon and at its rest position, the view also sho'wing amasking slide in one position of use;

FIG. 6 is a view sirnilar to FIG. 5 shewing the disc feeding means inits advanced position and the masking slide in another position 0f' use;

FIG. 7 is a partial view similar to FIG. 6, shcwing the operation 0fmeans for rendering the advancing mechanism ineffective to advance 'thedisc,

FIG. 8 is a partial section taker1 substantially along line 8 8 f FIG.5;

FIG. 9 is a partial section taken substantially a1ong line 99 cf FIG. 7;

FIG. 10 is a view similar to FIG. 5, showing a shutter mechanism andportions ofa tirner mechanism monted in position ofuse, the view being avertical section taken substantiqlly along line 1010 of FIG. 2, withparts rernoved for clarity;

FIG. 11 is a partial vertical section taken substantial1y along line1111 of FIG. 10;

FIG. 12 is a partial vertical s*cction taken substantially along line1212 0f FIG. 11 and showing the shutter mechanism at its rest positidnmasking theprdjecting apcrture of the projector;

FIG. 13 is a view similar to FIG. 12 showing the shutter mechanisrn inoperatioi1 10 effect prolonged projection under manual control;

FIG. 14 is.a view inelevation of one of the shutter blades of a pair ofshutter blades in the shutter mechamsm;

FIG. 15 is a side elevation of FIG. 14;

FIG. 16 .is a view in elevation of the other shutter blade;

FIG. 17 is a view in elevation take1i substantially along line 1717 ofFIG. 10, showing details of the shutter blade controlling mechanisni;and

FIG. 18 is a partial vertical elevation 011 an enlarged scale, Lakensubstantially alohg line 1818 of FIG. 10, and showing details of a timermechanisrn for varying the length 0f fractional-second projections.

In FIGS. 1 to 3, inclusive, the over-all arrangement of thetachistoscope of the pres nt invention may be seen. T he tachistoscopecomprises a projector generally indicated at 10, which is mounted upon asuitable base such as the lower portion 11 of a carrying case hereinillustrated. The base is preferably provided With suitable fest 12 atthe rear and a manually adjustable foot 13 at the freut in iluding handwhe'el 14 and a threaded stem 15 Whereby the angular 1*elatiohship ofthe base 10 any supporting surface may be vertically Varied so'as 10shift the image c1cted by the projector and cause it t0 fall upon anysuitable screen. The projector is preferably provided with a plurahty oftapered resilient feet 16 which projcct through suitable openings in aplate 17 mounted upon the base 11 by screws 18. Resilient washers 19 arepositioned between the projector and the plate 17 and friction fitfasteners 20 are sho ved up 0111101h@ tapered resilient fect 16 in orderto hold the projector upon the base, the resilient feet and washerspreventing transmission of motor hum from the base to the projector.

The projector comprises a pair of molded plastic housing parts, aforwrdpart 24 and a rear part 25, the two -fitting together along atransverse parting line 26 and being separately heid together bysuitable separable fastening means. A projecting lamp 27 is mounted in alouvered enge 28 in the rear housing part 25, the cage m0unting areflecting mirror 30 and suitable projecting lenses 31 and 32, thelarnp, mirror and lehses being optically centered along the projectingaxis of the projector. The forward housing part 24 inchldes a forwardwail 33 in which there is mounted a focusing lens tube 34 positionedafong the axis of projection. The focusing lens tube projects inwardlythrough a guiding flange35 in which there is mounted a spring 36 havinga detent which fits into a screw thread 37 on the surface of the tube.

The construction is such that the tube rnay be rapidly movedlongitudinally for large focusing adjustrnents. and rotated for finefocusing adjustments. The rear housing part 25 includes a forward wall38 in which there is a projecting aperature 39 (FIG. 4) positioned alongthe projecting axis. An abutment 40 is provided to limit inward movementof tube 34 (FIGS. 3 and The lamp 27 is connected by suitable wires to afan motor 41 which is mounted in the base and drives a fan 4-2. The basepreferably includes a well 43 in which a cord and plugin connector (notshown) may be coiled when not in use. The motor 41 is mounted upon anapertured plate 44 which is suitably mounted on the floor of the baseover an air inlet opening 45. The plate 17 is provided with a largeaperture 46 above the fan 42 and the laxnp mounting cage 28 is mountedupon a perforated plate 47 spanning the bottom of the rear housing part25, whereby air which is drawn through the opening 45 is projected intothe rear housing part 1:0 cool the projecting mechanism and preventoverheating of transparencies being projected. The air leaves thehousing through a louvered outlet 48 in the top of the housing part 25,the louvers preferably slanting forward so that bot air is blown awayfrom the face of the person operating the projector. The lamp 27 and themotor 41 are suitably connected into a circuit including a switch 49.

The upper forward edge of the rear housing part is recessed along theparting line 26 to provide a wide transverse slot 50 in the top of theprojector through which a disc 51 mounting a concentric row oftransparencies 52 may be inserted and rernoved. As seen in FIGS. 5 and6, the upper edge of the disc projects above the housing so that it maybe grasped for removal. The forward Wall 38 of the rear housing part isprovided with a plurality of raised ribs, such as radial ribs 53 (FIG.4), a circular inner rib 54 and a concentric outer rib 55, the forwardsurfaces of which lie in a common plane, also in which plane there islocated a raised flat area 56, so that the rear surface of the disc,which is pressed in engagement therewith by rneans to be described, ismaintained in a plane at right angles to the axis of projection. Thewall 38 is also provided with ribs 57, 58 and 59 which define a pockethaving a sernicircular bottom, and an upper mouth coextensive With theslot 50, the forward surfaces of these ribs being advanced from theplane previously described so as to engage the edge of the inserteddisc. The ribs, in combination with resilient means (to be described)which press the disc against the ribs defining said plane, compriserneans for rnaintaining the disc in a projecting plane, and for guidingthe sarne for rotation about the center of the disc. The disc 51 isprovided With a concentric row of radially etxending, elongatedapertures 60 adjacent the edge thereof, there being one aperture foreach transparency. The apertures are equidistantly spaced, as are thetransparencies, and so spaced that a definite angular advance at eachstep-by-step rnovement of the disc Will position one of thetransparencies in register With the projecting aperture 39. The aperture39 is laterally spacecl from the center of the disc.

Disc feea'ing means A mounting structure is mounted within the forwardhousing part 24, said structure including a disc feeding rneans mountingplate 65 having suitable stiffening fianges 66, 67 and 68 along certainedges thereof (FIG. 5). The plate is apertured and slit to provide pairsof tabs 70 and 72 which grip posts 71 and 73, respectively, integralwith wall 38. Another corner of platc 65 is retained against a pad 77 bya screw 75 and spacer 76, and the upper edge of the plate is retained bya tab 78 fitting a housing slot (not shown). Portions of the plate 65provide resilient means for pressing the disc 51 against the ribs 53, 55and surface 56, as follows: A locating dog arm 80 extends from theup'per left corner of plate 65 laterally and then downwardly and isprovided with a detent (not shown) which engages the apertures 60releasably to hold the transparencies in alignment with the projectingaperture. At the other side of plate 65 there is provided a resilient,inwardly bent aperture framing tab 81 which presses the disc against thesurface 56 around the projecting aperture.

A disc feeding lever 84 is rotatably mounted 011 the feeding mechanismmounting plate 65 as follows: The lever 84 is provided With a forwardlyprojecting cylindrical flange 85 which is journaled in a snugly fittingopening in the plate 65. A portion of the lever has arcuate edges,concentric with the flange 85, which are guided and retained by a pairof tabs 86 struck inwardly from the plate 65. The outer end of the levcr84 is provided witn an upwardly facing tab 87 and a downwardly facingtab 88 which respectively engage the upper and lower horizontal edges ofa large opcning 89 in a disc feeding slide 90. The slide is provicledwith a vertical flange (not shown) which is guided in a groove 91 moldedinto the forward wall of the rear housing part 24. A fiuted, upwardlyfacing thumb tab 92 is provided on a portion of the slide which projectslateral.y from the housing through a slot 93 along the parting line 26.

An opposite extension 95 of the lever 84, comprising a projeclingaperture masking flag, projects through a coucentric arcuate slot 96 inthe plate 65, the extension 95 having a narrow nach which is bentforwardly and then laterally for this purpose. A spring 97 is tensionedbetween the extension 95 and the flange 66 of the mounting plate wherebythe disc feeding mechanisrn is normally maintained in the position ofrest illustrated in FIG. 5. Depression of the slide results in partialrotation of the disc feeding lever, and when the slide is released thespring 97 returns the disc feeding lever and the slide to theirpositions of rest. The lever is thereby manually movable from a restposition' to an advanced position, as illustrated in FIG. 6, andautomatically returned when released. The lever 84 is provided with astop 98 which engages an abutrnent 99, fixed to the forward Wall of the.rear housing part (FIG. 2), whereby the extent of feeding. rnovement islimited.

The feeding lever 84 is provided with a concentric, resilient,downwardly projecting feeding finger 102 which is providcd at itsforward end with a fceding claw 103 adapted to engage each of theapertures 60 of the disc successively to effect the step-by-step feedingmovement thereof. Upon the return rnovement of the feeding lever to itsposition of rast the dog arm 80 prevents the feeding finger from movingthe disc in the reverse direction. During each advancing movement of thedisc the extension of the feeding lever obscures the projection apertureso as to eliminate any possibility of eyestrain due to shift. ing imageson the screen.

Shutter mechanz'sm The mounting structure includes a pair of posts 105projecting integrally forward from the wall 38 and provided Withcentral, threaded bores. The posts project forward to the same extent asthe spacer 76 (FIG. 5) and define therewith a plane in which ispositioned a. second vertical plate 106 of the mounting structure. Thescrew 75 and a pair of screws 107 engaging the posts 105 retain themounting plate 106 in forwardly spaced: relation to and parallel to themounting plate 65 (FIG, 11). The plate 106 is provided With a largeaperture 110, a portion of which registers with the projecting aper--ture 39 in the Wall 38, and through which a roller con necting pin 112projects from the extension 95 of the feeding lever. The pin 112 issnugly engaged in a transverse slot 113 in a connccting rneans slide 114guided for vertical movcrnent upon the face of plate 106 by a pluralityof flanged guide rollers 115 engaging vertical edges of the slide. Theslide normally rcsts at a position of rest, as indicated in FIG. 10, inwhich position a large notch 116 in the upper edge thereof registerswith the opening 110 so that the projection aperture is unrnasked by theslide 114.

A pair of shutter blades are mounted on the rear surface of the mountingplate 106, being maintained in elosely adjacent relation theret0 and toeach other by a plurality of shutter blade roller guides 120 (FIGS. 12

6 it unmasks the p'roje'c'ting aperture ihr0ugh its notch 116. Duringmost of the return movernent of the operating slide 114 both shuttetblades rernain at theircoeked positions, as will appear.

and 13) which respectively engage vertical edges of the shutters. Theshutter blades comprise a rear shutter blacle 121 and a forward shutterblade 122. The rear shutter blade has a rectangular notch 123 in itsupper edge which normally registers With the projeeting aperture and theaperture 110 in plate 106 when the shutter blades are at their restpositions, as illustrated in FIG. 12. 'The rear shutter blade also has alarge central rectangular opening 124 which normally registerswith theopening 110. Tl1e rear shuttei blade has a vertical slot 125 whichprovides a vertical edge for engagement of one of tl1e guide rollers120, while perrnitting an edge of the shutter blade to project beyondthe guide rollen This edge 'is provided with an upper latch operatingtab 126 and a lower latch operating tab 127. A spring mountingopening128 is provided in the shutter blade and the lower edge of the shutterblade is reeessed at 129 to provide clearance for a shutter bladereturning spring 130.

The forward shutter blade 122 is longer than the rear shutter blade andis provided with a projection aperture 135 which is normally masked by asolid portion of the rear shutter blade 121, as seen in FIG. 12.However, the front shutter blade may be raised independently of 1he rearshutter blade so as to unmask the projection aper- -ture, the imagebeing projeeted throughthe opening 135 and the notcl1 123 when tl1eshutter blades arein this relalive osition, as shown in FIG. 13. Theforward shutter bladeis also providedwith a large rectangular opening136 cf the Same size as opening 124, the openings 124 and 136 beingnorndally in register as seen in FIG. 12. The opening 136 permitsindependent rnovement of the fr0nt shutter blade without beingobstructed by the connection roller pin 112 which projeets therethrough.The shutter blade 122 is providcd With a vertical slot 137 whichprovides clearance for one of the roller guide pins 120 and is providedWith an apertured tab 139 for er1 gagement of one end of a tensionspring 133 which normally holds the freut shutter at its position ofrest.

The springs 130 and 138 are stretched when the shutter blades areelevated, by means to be described, and rapidly return the shutterblades independently of each other when they are released. T'ne springsare anchorecl at tneir lower ends to a horizontal flange 140 011 theplate Ihe mounting plate 106, for a purpose to be described.

When the roller connecting pin 112 is elevated during a step feedingmovernent ofihe disc, the operating slide 114 is elevated by engagementof -the pin With the slot 113, and simultaneously and coextensivelytherewith the two shutter blades are raised by engagement of the rollerpin with the upper edges of the apertures 124 and 136. Since the shutterblades *move togetner, the projecting aperture 39 is masked while theshutter blades are at rest as -seen in FIG. 12, while both sh'utterblades are elevated (n0t shown) and while the shutter blades are movingto their elevated or cockedpositions. lt is only Wl1en the rear shutterblade 121 has been returned to its position of rast and tl1e frontshutter blade 122 is in its elevated or cocked p0sition that theprojeoting aperture 39 is unmasked. It will be realized from theforegoing that upon 1elease of the feeding lever slide 90 the spring 97effects return of the operatingslide 114 so that Slmtter blade latchz'ngmechanism The mounting structure Within tl1e forward portion of theprojector housing ineludes a timer mechanism mount- 1'ng plate affixedthereto by rneans 02 a flange 146 suitably riveted to ihe plane 106. Theplate 145 is posi- 1ioned Vertically and extends forwardly normal to theplate 106. The mounting structure also includes a latch mounting plate147 which is mounted npon plate 145 and maintained in parallel, spaeedrelation to plate 145 by suitable bolts, nuts anal intervening spacers.The operating slide 114 mounts a cam plate 150 provided Witn an upwardlyprojecting carn edge 151 anti a downwardly projeeting cam edge 152-, thecanw edge 151 facing the plate 106 and tne carn edge 152 faeingforwardly away from the plate 106. I1re carn plate 150extendsysubstantially parallel to the plates 145 and 147 and is spaced1rorn the plate 147 (FI'GS. 10 and 11). The carn edge 151 engages aroller pin 153 on a cocking lever 154 which isloosely'journaled on theencl of a timer cam sha.ft 155 (FIG. 17) which is journaled in theplates 145 and 147. A grooved hub 156 fixed to lever 154 andconcentrically surr0unding the shaft 155 retains the bight of a wisnbonespring 157, one arm of which is retained by a pin 158 on an oppositely.directed arm of lever 154, and the other arm of which in retained by atab 159 on a retaining lever 160 pivoted at 161.

The retaining lever 160 is provided with a depenrling flange which hooksover an end of the cocking lever 154 to hold it in the positionillustrated in FIG. 17 when the shutter blades are elevated. Theretaining lever 160 is also provided with a d-epending flange 168 whichis pressed against an edge of a releasing lever 167 also pivoted ac 161and retained in the position illustrated in FIG. 17 by a spring 171.

The opposite encl of the releasing lever 167 bears against a pinproject'mg through an opening 176 in plate 147 from a fioating lever 177(FIGS. 17 and 18). Tl1e pin 158 on coek.ing lever 154 projects throughan opening in plate 147 and is fmed to a portion o-f the floating lever177. The fioating lever 177 is provided With a slot 178 in which isengaged a sector gear driving pin 180 attached to an eseapernent seotorgear 181 pivotally 1nounted an a pivot 152 fixed to the plate 145.

The arrangement is such that the releasing lever 160 rocks the floatinglever eounteroloekwise when the operating slide is moving upward,thereby through the medium of the pin 180 and s1ot 178 rn0ving the rnainsector gear 181 to its cocked position, as illustrated in FIG. 18. Asthe operating slide moves toward-its rest position the releasing leveris moved in such dlrection that the portion thereof in engagernent witht11e floating lever pin 175 mov s towardthe right in FE-G. 17, therebypermitting the po1cion of the floating lever arliacent thereto to pivotabout the pin 180 and causing a projection 133 thereon to engage thesnrfaee of a timer eam 184. As the slide continues to move downwardlythe pin 158 is driven toward the right in FIG. 18, thereby causing tnefloating 'lever 177 to rock connterclockwise about the projeotion 183which is now in engagernent with the eam 184. A spring 186 tensionedbetween the pin 175 and a pin 187 mountecl on the plate 147 tends tohold the projeetion 183 in engagement With the cam 184. However, thehairpin spring 157 is.eapable.of overcoming the spring 136 and drivesthe sector gear counterclockwise about its pivot 182, thereby eausingthe tfloating lever 177 to move counterclockwise abont the projection183. The seotor gear 181is in engagement With a pinion 190 which isfixed to an escapement ratchet 191, tlne peripheral ratchet teeth ofwhich are engaged by a double-armed, roeking esczipement dog 192. Theescapement mechanisrn causes the movement of sector gear 181 under theforce of the hairpin spring 157 to be regulated and constant.

The cam edge cf the timer can1 134 is so arranged that the length oftirne required for the projection 133 to engage the carn may beregulated. Such regulation is manually efiected througn the medium of atimer knob 193 projec-ting frorn the side of the casing. The knob 193 isprovidecl with a flange 194 having indioia thereon representingfractions of a seconcl (not shown) whioh may be set opposite an indexpoin-t 195 on ehe surface of the housing. The knob 193 is releasablyconnectcd to the tirner cam shaft 155 through the medium of a separabledriving connection, indicated generally at 196, whereby the housing maybe rernoved (FEG. Tl1e c-onnection cornprises a crossbar head fittedinto a siotted sockst 011 the inner extremity of the knob 193, detailsof which are not herein illustrated since such devices are weil known inthe art. By reason of this construction the duration of projection of animage may be accurately varied, for exarnple the projections may endurefor one twenty-fifty or one-tenth cf a second.

The release of rhe shutter blades in such controlled manner is eifeotedthrough the following mechanisrn: The tabs 126 and 127 on the shutterbinde 121 project through the elongated slot 144 and engage bladelatches 290 and 261 respectively, which are pivotally mounted onopposite sides of the mounting plate 147, during the cocking rnovementof Ihe shutter blades, At the termination cf the cooking movement thelatches 280 and 201 extend substantially normal to the shutter blades,as illustrated in FIG. 17. The upper latch 200 engages only the upperhorizontal edge of the notch 142 in b-lade 122, but the lower latch 201engages horizontal edges of both blades. When the latches are in thisposi-hion the upper latch is hold in latching engagernent by a hook 202on an end of the floating lever 177, and the lower latch 201 is hold inlatching engagornent by a hook on the end of a catch 203 pivoted on theplate 147. The cocking lever 154 has a cam 2534 thereon which engages aprojec tion on the catch 283 so that upon release of the cocking leverthe lo-wer latch 2111 is substantially immediately released. The catch253 is normally urged into looking engagement by a spring 295 asillustrated. The carn 284 also serves to move the catch out of the wayduring cool;- ing movernent and then releases the catch to engage thelatch at the terminabion of the cocking movement. The upper latch 2% isprovided With a cam surface 256 which normally engages the hook 292 whentl1e latch is released and rnoves the hook 262 out of the way againstthe force of spring 186, the spring snapping the hool into engagernentwith the latch at the termination of the cocking movernent.

During the return stroke o-f the opera-ting slide 114 the release lever160 is actuated and the cocking lever 154 starts to movecounterclockwise as previously described. Imrnediately upon suchrnovernent \the oarn 2M rnoves the ca tch 2113 to release the lowerlatch 201, whereupon tho spring 130 returns the shutter blade 121 to itsrest position. I-Iowever, 'the up-per latch 266 continues to hold thesecond blade 122 in its cocked position, as illustrated in FIG. 13. Theprojecting aperture 39 is thereby unmasked and an image projected. Theescapernent mechanism is now set in operation and a fraction of a secondlater, as determined by the position o-f the tirner cam 184, the upperlatch 259 is released and the second bla-de 122 returns to its rastosition as illustrated in FIG. 12.

Manually controlled duration The mounting plate 106 pivotally supports alever 2111 (FIGS. 10, 12 and 13) at pivot 211. One end of the leversupports a blade engaging pin 212 which projects through a slot 213 inthe plate 1116 and engagos a projection 214 on the shutter blade 122.The pin 212 is normally hold alt the bottom o f slot 213 by a spring 215stretched be tween the lever and a pin on plate 145. The opposite 8 endo-f lever 2111 is provided with a flange 216 which engages the lowor endof a plunger 217 vertically guided in iho casing part and provided Witha head 218 which may be engaged by the tip of a finger. When the plunger217 is depressed, while both shubter blades and the operating slide areat their Isst positions, ths shuhter blade 122 will be raised to unmaskthe projecting aperture 39 so that an image will be projected as long asthe operator desires. Upon releasing the plunger 217 the blade 122 isreturned by its spring 133 to again mask the projecting aporture, andplunger 217 is elevated by spring 215 and lever 216.

Partz'al image projeclz'on A second vertically guided plunger 2211provided with a l1ead 221 is guided in the top of casing part 24, thelower end of the plunger being releasably engaged in a slotted flange atthe top of a masking slide 222 slidably guided for vertical movement bytabs 223 struck frorn the mounting plate 65 (FIGS. 5 and 6). The maskingslide is provided with a large aperture 224 whioh is coex- -tensive insize with the projecting aperture 39, and which may be placed inalignrnent therewith by manually depressing the plunger 220. An edge ofthe slide is provided with an upper notch 225 which is so related to theaperturo 224 as to hold the aperture in such alignment when engaged by aV-shaped detent tip on a masking slide holding spring 226 mounted on theplate 65. The masking slide is also provided with a narrow horizontalslo=t 227 of the same width as the projecting aperture, but havingsubstantially less height than tne projecting aparture, in theillustrated exarnple being substantially onethird the he-ight t-hereof.The aperture 227 is defined by a pair of inwardly turned flanges 228whioh project toward the plane of the disc 51 through an elongatedaperture 229 in 1116 plate 65 (FIG. 11), the flanges sharply definingprojection through a por1ion of a transparency. The edge of the slide isalso provided with a plurality oi notches 236 so related to the spring226 that selected portions of a transparency may be projected.

The partial projection of a transparency is of importance in certaintraining projects, for example in training a student in the art of rapidreading. For exarnple, each transparency may have three 1ines of indiciathereon, possibly three series of nurnbers of three series of letters.Therefore, the utility of a Single disc of transparenoies may betripled, since there would be fifty-two lines for each disc oi fourteentransparencies. In utilizing such a. disc, the operator might so placethe aperture 227 as to permit pro-jection of an upper line, feed thedisc step by step fourteen 1111168, thei1 move the aperture 227 inposition to= projeot a central 1ine, and again feed the disc fourteensteps, and so on. It is, of course, obvious that the number of lines maybe increased 01' decreased and the notches 236 positioned accordingly.

The use of the entiro aper=ture 224 may be more desirable for otherpurposes, such as training artillery observers in aircraft, battleshipor tank recognition, in which case the disc could be provided withtransparencies having piotures covering the whole transparencies.

Repetition 0 instantaneous projections During the training uses asdescribed above, ehe operator may desire to repeat an image at splitsecond timing a nurnber of tirnes before proceeding to the nexttransparency. For this purpose means are provided for selectivelydisongaging the disc feeding arm 102 from feeding engagement With thedisc. Such means include a disengaging lever 235 pivotally mounted onthe Wall 39 at pivot 2411. The lever 235 projects outwardly tl1rough theslot 93 (F1G. l) and is provided with a manually engageable knob 236which lies directly below the slide 90, so Ihat it may be engaged andelevated by the fingers of the sarne har1d which engages the slide thumbpiece 92. When the lever 235 is so elevated a can1 surface 237 thereonis moved into the path 0f a raised corner 238 on the and of the feadingarm 1l2 adjacent the feading claw 103. The feeding claw is therebyalevated so that it cannot engage the apertures 60 in tha disc 51 (FIGS.7 and 9). Tharefore, depression of the slide 901'asults in coakingmovemant and raturn f the shutter blades as de scribad above, withoutadvancing the disc.

Having illustratad and describad a prefarred emb0diment 0 .E tl1ainvantion, it should be apparent to those slrillad in the art that thesame permits of modifications in arrangemerrt and detail. All suchmodifications as come wlthin the trua spirit and scdpe 0 f thefollow1'ng claims are eonsidarad to ba a part ofmy inven'tion.

I claim:

1. In a tachistoscope comprising a projector inclucling rneans torecaiva and rotatably guide a disc holding a concentric row oftransparencies, disc faeding rneans movabla from a rast position to anadvanced position for rotating said disc one step dm*ing each suchmovemant thereof whareby succassivaly to place said transparencias at aprojacting aperture, and means to return said feeding means to its rastposition; a pair of shutters, a mounting structure in said projactorinclucling rnaans for marintaining said shutters in planes parallel toand adjacant said disc, said shutters being normally at rast positionsand beir1g movable therefrom to cockad positions connecting meansoperatively connecting said feeding means and said shuttars during eachdisc advar'1cing movernent of said faeding maans f01' advancing saidshutters simultaneously to their cocked positions at each step movement0f the disc, a pair cf shutter latching maans mounted 011 said mountingstructura and including a pair 0f latchas respectivaly engagaabla withsaid shutters to hold them at their cocked positions, maans operativelyconnecting said feading means t0 said latching means during advanaingrnovemant of said feacling means for afieeting latched angagamant ofsaid latches Witl1 said shuttars at their cocked positions, saidshutters masking said projecting apertura while at their rast positions,while m0ving t0 their cocked positions and while at their cockedpositions, other connacting means operativaly connecting said faedingmeans and ona of said latching means during return movarnant of saidfaeding rneans to its rast position for afifecting ralease of 011a ofsaid latches frorn latching engagernant with ona of said shutters, apair of resilient means raspactively biased batween said shutters andsaid mounting structure and individually operative to return saidshutters to theirrest positions whan raleased by said latching, means;and timing mechanism oparatively associatad with said pair of latchingmeans for effecting release of the othar of said latches from itsshuttar at a time interval aftar release of said one shutter, saidprojecting aperture being unmasked after said one shutter has raturnedto its rast position and while said otl1ar shutter rarnains at itscockecl position.

2. In a tachistoscope comprising a projactor including means to receivaand rotatably guide a disc holding a concentric row of transparencias,disc feeding means normally ramaining at a rast position and movable toan advzinced position for rotating said disc one step duri ng each suchmovement thareof whereby successively to place said transparencies at aprojectlng aperture, and means to return said feeding rriaans to itsrast osition; a pair of shuttar blades, a mounting structura in saidprejector including guiding means for ma intaining said blaclas inplanes parallel to and adjacent said disc, said blades being normally atrast positions and being movable therefrom to cocked positions,connacting rneans oparatively connecting said feeding rneans and saidblades during each disc advancing movement of said feading means foradvancing said blades simultaneously to their coc kad positions at eachstep movement of the disc, a pair of blade latching means mounted onsaid mounting structure and including a pair of latches respactivelyengageable with said blades to hold them at their cocked positions,means operatively connecting said feeding maans to said latch- 10 ingmeans during advancing movernent cf said faeding means for effectinglatchad engagament of said latches with said blades at their cockedpositions, said bladas masking said projecting apartura While at thairrast positions, while rn0ving to their cocked positions and whi1a attheir cocked positions, other connecting meaus operatively connectingsaid feeding means and one of said latching means during return movementof said faacling means to its rast position for eflecting relaasa of oneof said latches from latching engagement With orte of said bladas, apair of resiliant mean's raspectively biased batwaen said bladas andsaid mounting structure and individually operative to return said bladesto their rast positions Whan released by said latching means, and timingmechanism operatiVely associated with said pair of 1atching means foraffecting release of the other of said latches from its blade at a timeintarval aftar release of said ona blade, said projacting aparture beingunmaskad after said one blade has raturnad to its rast position andwhila said other blade remains at its cocked position.

3. In a tachistoscope comprising a projector including means to receiveand rotatably guide a disc holding a concentric row of transparancies,disc feading means movable from a rast osition t0 an advanced position'f0l rotating said disc one step at each advancing movement thereofwharaby succassively to place said transparencies at a projectingaperture, means to advance saidfeeding means, and means to return saidfaading means to its rast position; a pair of shutter blades, a mountingstructura in said projector including guiding means for 'mairitainingsaid blades in planes parallel to and adjacent said disc, said bladesbaing normally at rast posltions and being movable therefrom to cockadpositions, connecting rneans operatively connacting said feeding meansand said blades during each disc advancing movernant 'of said feedingrneans for advancing said blades simultaneously to their cockedpositions at each step movement of the disc, a pair of blade latchingrneans rn0unted 011 said mounting structure and including a pair oflatches respectively engageable with said blades to hold tham at their-cocked pnsitions, maans operatively connecting said feedlng rneans tosaid latching mazins during aclvancing movement of said feeding meansfor effacting latchecl engagament of said latches with said blades attheir cocked positions, said bladas masking said projecting aperturewhile at their rast positions, while moving to thair cocked and timingmechanisrn operatively associated With said pair of latcning rneans foreffecting release of the othar of said latches from its blade at a tirneintarval after release of said one blada, said pl'oje'cting aparturebeing unmaskecl aftar said one blade has raturned to its rast positionand whilesaid other blade remains at its cockad position, said tirningmechanism comprising means selec- .tively to varv said time intarval.

4. In a tachistoscopaeomprising a projector including .m'eans t0 receivaand -rotatably guide a disc holding a concentric row 0f transparencies,disc feeding means rncvable frorn a rast position to an advanced'p0sition for rotating said disc ona step ateach advancing movemantthereof whereby successivaly to plaea said transparenaies at aprojacting aparture, and means to aclvance and return said faedingrneans; a pair of shutterblades, amounting structure in said projectorincluding guiding rneans for maintaining said blades in planes parallelto and adjacant said disc, said blades being normzilly at rast positionsand being movabla therafrorn'to cocked positions,

connacting maans oparatively connacting said faading maans and saidbladas during aach advancing movarnant of said faading rnaans foradvancing said bladas simultaneously to thair cockad positions at aachstap rnovarnant f tha disc, a pair of blada latching maans mountad onsaid mounting structure and including a pair of latchas raspactivelyangagaabla with said bladas to hold tharn at thair cockad positions,maans oparatively connacting said faading rnaans to said latahing maansduring advancing rnovamant 01. said faading maans for afiacting latchadangagemant of said latchas With said bladas at thair cockad positions,said bladas masking said projacting apartura whila at thair rastpositions, whila moving to thair cockad positions and Whila at thaircockad positions, othar connacting rnaans oparativaly connacting saidfaading maans and ona of said latching maans during return rnovarnant ofsaid faading means to its rast position for atfacting relaasa of ona ofsaid latchas from latching angagamant with ona of said bladas, a pair ofrasiliant means respactivaly biased batwaen said bladas and saidmonnting structura and individually operative to raturn said bladas tothair rast positions whan ralaased by said latching rnaans tirningmachanisrn oparativaly associated with said pair of latching maans foreflfacting ralaasa cf tha othar of said latchas from its blade at atirne intarval aftar relaasa 0f said ona blada, said projacting aparturabaing unmasked after said ona blada has raturnad to its rast positionand while said other blada ramains at its cocked position, and manualrnaans individually to advanca said othar blade to its cockad posidenwharaby to unmask said projacting aparture without advanaing tha disc orafracting oparation of said latching means.

5. In a t-achistoscopa cornprising a projactor including maans toracaiva and rotatably guida a disc holding a concentric row oftransparancies, disc faeding rnaans movabla from a rast position to anadvancad position for rotating said disc ona stap at aach advancingmovamant tharaof wharaby succassivaly to placa said transparencias at aprojecting apartra, and maans to advance and ra turn said faading maans;a pair of shutter blaclas, a mounting structura in said projactorincluding guiding maans for maintaining said blades in planas parallelto and adjacant said discs, said blades baing norrna1ly at rastpositions and baing movabla tharafrom to cockad positions, connactingmaans oparatively connacting said faading maans and said bladas duringaach advancing movamant of said faading maans for advancing said bladassimultanaously to thair cocked positions at aach stap movamant of thadisc, a pair of blada latching maans mountad 011 said mounting structuraand including a pair of latches raspactivaly angagaabla with said bladesto hold tham at thair cockad positions, maans oparativaly connectingsaid faading maans to said latching rnaans during advancing movamant ofsaid faading maans for affecting latchad angagamant of said latchas Withsaid bladas at thair cockad positions, said blades masking saidprojacting apartura Whila at thair rast positions, While rnoving tothair cockad positions and whila at thair cockad positions, otharconnacting rnaans oparativaly connacting said faading maans and ona ofsaid latching maans during return movarnant of said faading maans to itsrast position for afiacting ralaasa of ona of said latchas from latchingangagamant With ona of said bladas, a pair of resiliant maansraspactivaly biasad batwaan said blades and said mounting structure andindividually operative to ratnrn said bladas to thair rast positionswhan releasad by said latching rnaans, timing maahanism operativalyassociatad with said pair of latching rnaans for affecting ralaasa oftha othar of said latchas from its blada at a tima intarval afterralaasa 0f said ona blada, said projacting aparture baing unmaskad aftarsaid ona blada has raturnad to its rast position and whila said otharblada remains at its cockad position, said faading means cornprising amambar normally in faading engage- 12 mant with said disc, and maarlsf0r salactivaly disengaging said marnbar frorn said disc in ordar t0rapaat tha projaction of a salectad imaga.

6. In a tachistosaoria comprislng a projector including means to recaiveand rotatably guida a disc holding a concantric row of transparancies,disc faading maans movabla from a rast position to an advancad positionfor rotating said disc ona stap at aach adv-ancing rnovarnant thareofwharaby succassivaly to place said transparancies at a projactingaparture, and means to advanca and return said faedlng maans; a pair ofshuttar bladas, a mounting structura in said projector including guidingmaans for maint-aining said bladas in planas parallel to and adjacantsaid disc, said bladas being normally at rast positions and baingmovabla tharafrom t0 cockad positions, connecting maans oparativelyc'onnacting said faading maans and said bladas during aach advancingmovemant of said faading means for advancing said blades simultaneouslyto thair cockad positions at aach stap movarnant of tha disc, a pair ofblada latching rnaans mountad an said mounting structura and including apair cf latchas raspactively angagaabla With said bladas to hold tham atthair cocked positions, rnaans oparativaly connacting said faading maansto said latching rnaans during advancing movamant of said faading meansfor effecting latchad angagamant cf: said latches with said bladas atthair cocked positions, said bladas masking said projacting aperturewhila -at thair rast positions, whila moving to thair cockad positionsand whila at thair cockad positions, othar connacting maans oparativalyconnacting said faading rnaans and ona of said latching maans duringraturn movement of said faading maans to its rast position f0r elfactingrelaasa of ona of said latches from latching angagemant with ona of saidblades, a pair of rasiliant maans raspactivaly biasad batwaan saidbladas and said mounting structura and individually operative to raturnsaid bladas to thair rast positions whan raleasad -by said latchingrnaans, timing machanisrn oparativaly associatad with said pair oflatching maans for afi?ecting raleasa cf tha othar of: said latchas fromits blada at a tima intarval aftar ralaase of said ona blada, saidprojacting apartura baing unmasked after said ona blada has raturnad toits rast position and whila said other blade ramains at its cockedposition, said faading rneans cornprising a marnbar normally in faedingangagemant With said disc, maans for salactivaly disangaging said mambarfron1 said disc in Order to repeat the projection of a selacted imaga,said faading maans comprising a first manually engagaabla levar movablealong a path, and said disangaging maans cornprising a sacond manuallyangagaabla levar rnovable along a continuation of said path, said lavarsbalng simultaneously angagaable by tha digits of ona band.

7. In a tachistoscopa cornprising a projector including maans to raceivaand rotatably guida a disc holding a concantric row of transparancies,disc faeding maans norm ally ramaining at a rast position and movabla toan advancad position for rotating said disc ona stap during aach suchmovemant tharaof wharaby succassivaly to placa said transparancias at aprojacting apartura, and means to raturn said faading rnaans to its rastposition; a pair of shutter blades, a mounting structnra in saidprojactor including guiding maans for maintaining said bladas in planasparallel to and adjacant said disc, said bladas baing normally at rastpositions and baing movabla tharafrom to cockad positions, connactingmeans oparatively connacting said feading rnaans and said bladas duringaach disc advancing movamant of said faading maans for advancing saidbladas simultanaously to thair cockad positions at aach stap movarnantof tha disc, a pair of blade latching maans mountad on said mountingstructura and including a pair of latchas raspectivaly angagaabla Withsaid bladas to hold tham at thair cockad positions, maans oparativelyconnacting said faading maans to said latching maans during advanciugmove- 13 ment of said feeding means for eifecting latched engagement ofsaid latches with said blades at their cocked positions, said bladesmasking said projecting aperture While at their rast positions, whi1emoving to their cocked positions and while at their cocked positions,other counecting means operatively connecting said feeding rneans andone of said latching means during return movement 0f said feedingmeans.to its rast Position for effecting release of one of said latchesfrom latching engagement With one of said blades, a pair of resilientmeans respectively biased between said blades and said mountingstructure and individually operative to return said blades to their rastpositions when released by said latching means, timing mechanismoperatively associated with 14 said pair of latching means for eflectingrelease of the other of said latches from its blade at a tirne intervalafter release of said one blade, said projecting aperture being unmaskedafter said one Made has returned to its rast position and while saidother blade remains at its cocked position, a masking slide mounted onsaid mounting structure for movement past said projecting aperture, saidslide having a slot therein of lesser width than a transparency, andmeans selectively to retain said slide at a plurality of positions withsaid slot in projecting alignment with selected portions of saidprojecting aperture.

N0 references cited.

